CLDN1 and inflammation: In addition, we observed that L. paracasei ATG-E1 increased the expression of tight junction genes claudin-1 and occludin-1 in the ileum, suggesting that L. paracasei ATG-E1 may improve barrier integrity impaired by PM10D. These results indicate that L. paracasei ATG-E1 has beneficial effects on immunity and barrier function in the intestine during PM10D-induced airway inflammation.